Intertube burner



y 24, 1956 H. SMITH EI'AL 2,755,781

INTERTUBE BURNER Filed June 21, 1952 INVENTORS 54 El /c H. 5M1 TH ATTORNEY INTERTUBE BURNER Eric H. Smith and Roy E. Baharian, Worcester, Mass, assignors to Riley Stoker Corporation, Worcester, Mass, a corporation of Massachusetts Application June 21, 1952, Serial No. 294,854

4 Claims. (Cl. 122-235) This invention relates to an intertube burner and more particularly to a fuel burning apparatus for use in the furnace of a steam generating unit.

in the burning of fuel for the generation of steam it is sometimes desirable to introduce the fuel without appreciable disturbance of water wall tubes. This is particularly true in the burning of gas because of the fact that the volume of material necessitates a large burner area and, if ordinary burners were used, water wall tubes would have to be removed from a considerable portion of the wall of the furnace probably by bending them rearwardly and laterally in that area. Not only would radiation area be reduced appreciably, but the bending of the tubes involves an added expense and at the same time presents certain problems as to where the bent portions of the tubes can be located in the limited space available. These problems brought about the use of the intertube burner, which provides for the burning of the fuel without disturbance of the ordinary water wall tube arrangement. Such a burner is shown in the patent to Kuhner No. 2,392,822 issued January 15, 1946. Some of the prior art apparatus, however, have had some rather objectionable characteristics. For instance, they are often very expensive, a particularly undesirable feature in installations where the gas burner is only intended for intermittent use as an auxiliary to separate oil and coal burners. in many cases the mixing is poor, resulting in poor combastion and low efficiency as well as smoking. Also, most of the prior art devices have no provision for changing the luminosity of the flame for control of superheat. The present apparatus obviates the shortcomings and the difficulties encountered in the prior art in a novel manner.

it is therefore an outstanding object of the present invention to provide an intertube burner which is simple in construction and inexpensive to manufacture.

Another object of the invention is the provision of a gas burner in which mixing of the fuel and the combustion air is very thorough.

A further object of the instant invention is to provide an intertube burner which permits of adjustment of the luminosity of the flame.

A still further object of the invention is the provision of intertube burner which is very rugged and which will give a long life of useful service.

it is another object of the invention to provide an intertube burner which permits the burning of gas and oil in the same portion of the furnace.

A further object of the present invention is the provision of an intertube burner in which the water wall tubes of the furnace are only slightly disturbed and are subject to very little loss of radiant heat from the furnace because of rearrangement.

With t .ese and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

The character or" the invention, however, may be best understood by reference to certain of its structural forms,

Patented July 24, 1956 as illustrated by the accompanying drawings in which:

Figure 1 is a vertical sectional view of a portion of a furnace embodying the present invention,

Figure 2 is a horizontal sectional view of the invention taken on the line 2-2 of Figure 1 and somewhat enlarged,

Figure 3 is a View of a portion of the apparatus of the invention taken on the line 3-3 of Figure 2, and

Figure 4 is a horizontal sectional view of another embodiment of the invention.

For the purposes of the discussion which follows, the portion of the furnace wall in which the apparatus resides will be thought of as the front wall, so that the expression longitudinal will mean perpendicular to the wall, the expression transverse will mean parallel to the wall, the expressions inner or forward will mean toward the inside of the furnace wall, and the expressions outer or rearward will mean toward the outside of the wall.

Referring first to Figure 1, which best shows the general features of the invention, the apparatus, generally designated by the reference numeral 19, is shown as comprising substantially vertical forward water wall tubes 11 which reside in the plane of the wall and rearward water wall tubes 12 which are bent to a position rearward of their normal positions in the wall. The area within which seine of the water wall tubes are bent to a rearward position may be thought of as the burner opening and refractory is not used in this area. A housing 13 surrounds the burner opening and, in the preferred embodiment, has a double-wall structure. The housing is divided by av partition 14 into two chambers 15 and 16, each having entrances 17 and 18, respectively, for combustion air. The entrance 17 has a damper 19 selectively operated by an actuating shaft 2%, while the entrance 18 has a damper 21 operated by an actuating shaft 22. A main gas conduit 23 enters the chamber 16 and connects to a transverse conduit 24 from which branch conduits 25 run to the lower portions of vertical gas pipes 26. In a similar manner, a main gas conduit 27 enters the chamber 15 and connects with a transverse conduit 28 which is connected to vertical gas pipes 29 through branch conduits 30. The chamber 15 is provided more or less centrally with an auxiliary or igniter burner such as an oil burner 31, and the chamber 16 is provided with a similar burner 32. The chamber 15 is provided with a peep-hole 33 and the chamber 16 has a somewhat similar peep-hole 34, although the latter is necessarily provided with an elongated tube 35. For all intents and purposes, the apparatus 10 consists of two similarly equipped chambers 15 and 16, so that it will be necessary to describe only one specifically.

Referring next to Figure 2, wherein is shown in a more specific manner the structure of the gas burner. This view shows particularly well the staggered relationship between the forward water wall tubes 11 and the rearwardly-bent tubes 12. In the original, undisturbed water wall, the tubes were arranged in side-by-side relation with only a very small space between them and this transverse relationship is retained in the practice of the invention. However, in a direction longitudinal of the furnace the forward and rearward tubes are displaced, the outer part of the tubes 11 and the inner part of the tubes 12 being slightly coextensive. A baflle member 36 is welded to the outer or rearward part of each of the tubes 11 and is provided with balfie plates 37 extending on either side thereof in a manner to be explained more fully hereinafter. It should be noted that a gas pipe 29 is provided directly behind each forward water wall tube 11 and just touches the surface of the bafile member of its respective tube 11. Each gas pipe is also provided with jet openings 38 arranged in a staggered relationship along the pipe. Each rearward water wall tube 12 is provided with vertical protuberances 39 which may be formed of curved strip welded to the tube 12; these protuberances extend from diametrically opposite sides of the tube 12 and extend toward an adjacent gas pipe 29. The axes of the gas pipes 29 and the rearward water wall tubes 12 lie in the same vertical, transverse plane. In this figure of the drawings it is to be particularly noted the manner in which a rearward water wall tube 12 has been additionally bent outwardly and transversely to permit the passage of the oil burner 31 between two forward tubes 11.

Referring next to Figure 3 which is a vertical view of a portion of the burner looking toward the back side of a forward tube 11, showing a baffle member 36 and the inside forward surface of a gas pipe 29. This View shows the arrangement of the jet openings 33 in a vertical direction with alternate openings directed to one side and another of the'tube 11. The baffle member 36 is provided, as has been stated, with bafile plates 37. The member 36 proper is formed from plate metal material and has a main body portion which is of generally elongated rectangular shape with the baflle plates extending laterally therefrom. The bafile plates are rectangular and are staggered vertically of the length of the member. As is evident from the drawing, each jet opening 38 is directed parallel to a corresponding baflle plate. The main body portion of the baflle member is bent around the forward water wall tube 11 to which it is welded but the bafile plates are not so bent, so that they extend more or less tangentially to the surface of the tube 11 and form a flat, vertical surface extending at an angle of around 45 degrees to a transverse plane. The jet openings 38 are directed parallel to the baffle plates 37 so that gas fiow is generally parallel to these plates. The wedge-shaped space between each baffle plate 37 and its respective tube 11 is filled with weld metal to support the bafile plate and to absorb radiant heat from the furnace for transmittal to the water in the tube.

The operation of the apparatus will be evident from the above description in conjunction with the drawings. Combustion gas enters the conduit 27 and passes into the transverse conduit 28 from which it is distributed through the branch conduits 30 into the gas pipes 29. The gas leaves a gas pipe 29 through a jet opening 38 and impinges on the corresponding baffle plate 37. In the meanwhile, air has been admitted through the entrance 17 in accordance with the setting of the damper 19 as determined by use of the actuating shaft 20. The air flows into the chamber and moves toward the wall of the furnace. It reaches the barrier formed by the aligned gas pipes 29 and rearward water wall tubes 12; the only passage through this barrier into the furnace is in the space between the side of each gas pipe 29 and the protuberance 39 which extend toward it from a tube 12. This space is just suflicient to give the desired air flow velocity for good combustion. The air flows longitudinally through the above-described space and intersects the gas stream issuing from a jet opening 33, at the same time impinging on a baffle plate 37. The resultant of this action is thorough mixing of gas and air; the mixture passes outwardly through the nozzle-like passages between the baffie plate and the adjacent rearward water wall tube 11 and between the outer end of the bafile plate and the adjacent forward water wall tube with its corresponding bafile member.

Another embodiment of the invention which is particularly useful with furnaces of the type wherein the water wall tubes are spaced a considerable distance apart is shown in Figure 4. Water wall tubes 50 are spaced a distance approximately equal to the diameter of a tube and are provided with baffle members 51 similar to those shown and described in connection with the above embodiment. Gas pipes 52 reside behind the tubes 50 and are provided with nozzle apertures 53 which are directed toward a baflle plate 54 forming a part of the member 51. Between each pair of water wall tubes 50 and slightly therebehind is a vertically-supported cylindrical column 55 of refractory material. .These occupy somewhat the same positions as do the rearward water wall tubes 12 of the previously-described embodiment of the invention. A damper member 56 is positioned between each water wall tube and the columns which lie behind and adjacent to it. Each damper member 56 is of generally aerodynamic horizontal cross-sectional shape and is mounted for pivotal movement about a vertical axis which lies approximately on a line joining the axes of the tube 50 and the column 55.

The operation of this embodiment of the invention is similar to that of the first embodiment. However, the space between a gas pipe 29 and its adjacent rearward tube 12 in the first embodiment was somewhat fixed by the standardized diameter of water wall tubes and this necessitated the provision of protuberauces 39 to restrict the air flow through that space. In the present embodiment the refractory column 55 may be selected of any desirable size and may be changed after installation of the burner to fit certain operating conditions. The damper 56 serves to direct the flow of air and gas against the battle plate 54 to promote mixing of gas and air. Since the damper is externally adjustable, it is possible to regulate the amount of mixing which takes place at the baffle plate and, thus, to determine the size, length, and luminosity of the flame. This permits adjustment of the degree of superheat.

It is obviou that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. It is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come with the scope claimed.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:

1. A burner for a furnace comprising a furnace wall having an opening therein, a series of parallel water wall tubes lying on the inside surface of said wall and passing over the said opening, a gas pipe extending parallel to each water wall tube coextensively with the said opening and rearwardly thereof, a baffie member extending between each gas pipe and its respective water wall tube, a plurality of jet openings in each pipe for directing gas toward the respective water wall tube and generally parallel to the said batfie member, the openings being located rearwardly of the respective tube and shielded from furnace radiation, means for supplying air rearwardly of the gas pipes and water tubes, and columns extending parallel to the tubes coextensively with the opening and each column being situated between and rearwardly of a pair of said tubes, the jet openings being spaced substantial distances apart along the pipe and alternate openings directed on opposite sides of the tube, a section of the baffle being located adjacent each opening and extending away from the tube only on the side thereof toward which the jet is directed, so that each jet tends to impinge on the said section of the baffle so that an opening uninterrupted by a bafiie section is located on the side of the tube toward which the jet is not directed the baflle sections which extend between two adjacent water tubes being offset with respect to each other.

2. A burner for a furnace comprising a furnace wall having an opening therein, a series of parallel water wall tubes lying on the inside surface of said wall and passing over the said opening, a gas pipe extending parallel to each water wall tube coextensively with the said opening and rearwardly thereof, a battle member extending between each gas pipe and its respective water wall tube, a plurality of jet openings in each pipe for directing gas toward the respective water wall tube and generally parallel to the said bafiie member, the openings being located rearwardly of the respective tube and shielded from furnace radiation, means for supplying air rearwardly of the gas pipes and water tubes, the jet openings being spaced substantial distances apart along the pipe and alternate openings directed on opposite sides of the tube, a section of the bafile being located adjacent each opening and extending away from the tubes only on the side thereof toward which the jet is directed, so that each jet tends to impinge on the said section of the bafile, so that an opening uninterrupted by a baffle section is located on the side of the tube toward which the jet is not directed, the bafile sections which extend between two adjacent water tubes being offset with respect to each other.

3. A burner for a furnace comprising a furnace wall having an opening therein, a series of parallel water wall tubes lying on the inside surface of said wall and passing over the said opening, a gas pipe extending parallel to each water wall tube coextensively with the said opening and rearwardly thereof, a baffle member extending between each gas pipe and its respective water wall tube, a plurality of jet openings in each pipe for directing gas toward the respective water wall tube and generally parallel to the said bafile member, the openings being located rearwardly of the respective tube and shielded from furnace radiation, means for supplying air rearwardly of the gas pipes and water tubes, and columns extending parallel to the tubes and coextensively with the opening and each column being situated between and rearwardly of a pair of said tubes, the jet openings being spaced substantial distances apart along the pipe and alternate openings directed on opposite sides of the tube, a section of the baflle being located adjacent each opening and extending away from the tube only on the side thereof toward which the jet is directed, so that each jet tends to impinge on the said section of the bafiies, so that an opening, uninterrupted by a bafile section, is located on the side of the tube toward which the jet is not directed, the bafile sections which extend between two adjacent water tubes being offset with respect to each other, each of the said columns consisting of a water wall tube which is bent rearwardly to lie between a pair of gas pipes.

4. A burner for a furnace comprising a furnace wall having an opening therein, a series of parallel water wall tubes lying on the inside surface of said wall and passing over the said opening, a gas pipe extending parallel to each water wall tube coextensively with the said opening and rearwardly thereof, a bafile member extending between each gas pipe and its respective water wall tube, a plurality of jet openings in each pipe for directing gas toward the respective water wall tube and generally parallel to the said bafile member, the openings being located rearwardly of the respective tube and shielded from furnace radiation, means for supplying air rearwardly of the gas pipes and water tubes, and columns extending parallel to the tubes coextensively with the opening and each column being situated between and rearwardly of a pair of said tubes, the jet openings being spaced substantial distances apart along the pipe and alternate openings directed on opposite sides of the tube, a section of the bafile being located adjacent each opening and extending away from the tube only on the side thereof toward which the jet is directed so that each jet tends to impinge on the said section of the baifie, so that an opening, uninterrupted by a baflle section, is located on the side of the tube toward which the jet is not directed, the baffie sections which extend between two adjacent water tubes being offset with respect to each other, each of the said columns consisting of an elongated cylinder formed of refractory material.

References Cited in the file of this patent UNITED STATES PATENTS 1,994,447 Bailey et al. Mar. 12, 1935 2,022,427 Lucke Nov. 26, 1935 2,064,366 Bailey Dec. 15, 1936 2,119,580 Hardgrove June 7, 1938 

